W202 immobilizer issue

[babz]

Ok guys, a bit of a weird one but ill try to explain the best I can.

Today drove the car as normal and went to the petrol station - no issues.

Got back into the car and realized I hadn't locked the door but the immobilizer had activated - which it does normally. So I locked the door using the remote and unlocked it and went to start the ignition and it just kept turning over (as if the immobilizer hadn't deactivated.)

So I repeated the locking/unlocking with the remote again but still the same, lights on the rear view were flashing constantly whether the car was locked or unlocked.

After about 30 mins of looking like an idiot on the forecourt I tried pointing the IR on the remote to the drivers side door handle (on the red/green LED lights where you find the lock) and pressed the button, held for 5 secs and it unlocked the door - no constantly flashing lights on the rear view, just the green light to say the immobilizer is deactivated. Went to turn the key and the car started - THANK GOD!

So drove back home, locked/unlocked/started the car and all seems to be back to normal. So my question is - what happened? Its not the 1st time I've left the car unlocked, its always been OK to lock/unlock and drive off. As you can appreciate Im a little wary to use the car now as Im potentially a sitting duck if the problem comes back.

As usual ALL input is appreciated gents. Thanks

 

[babz]

Just to elaborate a bit further, this morning it happened again, this time it was locked/ unlocked as normal but it still failed to deactivate the immobilizer. After 7-8 attempts of locking/unlocking it knocked off the immobilizer and fixed itself. Any ideas on whats going wrong?

 

[Dec]

Did the Red & Green LEDS on the mirror and door handle flash alternately or together?

Dec

 

[babz]

the lights were flashing together at the same time. the indicators would also flash for upto 15 seconds after locking or unlocking.

I have since then replaced the batteries in the key and so far (touch wood) it seems to have solved the issue. it seemed a little strange as the key seemed to work fine locking and unlocking but it seems it just didnt have enough power to knock off the immobilizer.

 

[samthesidecar]

Mine has been doing the same recently, didn't occur to me that it might be remote batteries.

 

[babz]

OK so unfortunately this thread has to go up again, today i spent almost an hour trying to knock off the immobiliser on the 202. Before it used to take anything up to 10 attempts to deactivate the immobiliser but now its not even worth counting.

so it seems that 6months is the life span of 2 new key fob batteries or that there is an underlying issue.

after getting a little frustrated i pressed the single button on the fob repeatedly 4 or 5 times and PRESTO it deactivated, but i cant afford to get stranded everytime the immobiliser feels like it.

any ideas what i can check/do?

Thankis in advance

 

[Dec]

Are you using good quality CR2025 batteries with plenty of sell by time left on the packaging.

Dec

 

[babz]

Thanks for your input Dec, I'm not sure if the batteries were old stock but I have changed them regardless and it has resolved my issue.